Method of producing tape-shaped assembly of elastic filaments

ABSTRACT

METHOD OF PRODUCING TAPE-SHAPED ASSEMBLY OF MELT SPINNING AN ELASTIC POLYMER INTO FILAMENS, COOLING THE FILAMENTS, ARRANGING THE FILAMENTS WHILE STILL TACKY TO EFFECT SIDE-BY-SIDE CONTACT WITH ADJACENT FILAMENTS AND TO FORM A UNITARY ASSEMBLY, AND DRAWING THE ASSEMBLY TO ADJUST   THE SEPRATING ELONGATION (DEFINED IN SPECIFICATION) BETWEEN ADJACENT FILAMENTS TO LESS THAN 150%.

q 12, 1972 HIROFUMI NISHIZAWA ETA!- 3,690,973

METHOD OF PRODUCING TAPE-SHAPED ASSEMBLY OF ELASTIC AMENTS Filed Aug. 1969 INVENTORS OFUMI NIS AWA GEO KITAU M O-SUMOTO H K! KOMAGATA HIROSI MATSUMOTO %%d9w%, hi

ATTORNEYS United States Patent Ofice 3,690,973 Patented Sept. 12, 1972 US. Cl. 156-167 4 Claims ABSTRACT OF THE DISCLOSURE Method of producing tape-shaped assembly by melt spinning an elastic polymer into filaments, cooling the filaments, arranging the filaments while still tacky to effect side-by-side contact with adjacent filaments and to form a unitary assembly, and drawing the assembly to adjust the separating elongation (defined in specification) -between adjacent filaments to less than 150%.

This invention relates to a novel tape-shaped assembly of elastic filaments and its production.

It is known to use elastic yarns such as spandex yarns as yarns for making various knit or woven fabrics or articles. However, since these yarns are elastic, it is difficult to handle them before knitting or weaving. Especially, it is difficult to properly arrange or hold the elastic yarns for feeding to the knitting or weaving machine. Thus, for example, in knitting elastic fabrics, typically the so-called power net by using such elastic yarns or filaments as warps, it has been conventional to pass them in a warping machine and then feed to a knitting machine. However, the Warping machine is very expensive. Further, the warping operation of elastic yarns is difficult requiring a very high skill. Thus, the warping process occupies a great weight in the production of power nets.

Therefore, it is a principal object of this invention to provide an elastic filament assembly which is easy to handle and can be fed directly to a knitting machine or weaving machine without the necessity of the conventional warping machine or operation for warping elastic filaments.

Another object of the present invention is to provide a method for simply and economically producing the above mentioned tape-shaped assembly of elastic filaments.

Still other objects is to provide a measure for controlling separability of the above mentioned assembly into the individual elastic filaments.

Other objects, features and advantages of this invention will be apparent from the following description.

Briefly, a tape-shaped assembly of elastic filaments according to this invention comprises a plurality (at least of elastic filaments arranged in parallel and in a single plane and bonded together in the form a tape, the bonding power being such that the tape can readily be separaed into the individual filaments. Preferably, the separating elongation of the filaments as measured in a manner hereinafter defined is less than 150%.

The invention will be explained in more detail partly by referring to the accompanying drawings wherein:

FIG. 1 is a schematic and enlarged cross-section of an elastic filament assembly embodying the present invention;

FIG. 2 is a schematic perspective view showing the method for measuring a separating elongation; and

FIG. 3 is a schematic view showing an apparatus to produce an elastic filament assembly according to this invention.

Referring to FIG. 1, a tape-shaped elastic yarn assembly A of this invention comprises a plurality of elastic filaments 1 arranged side by side in parallel in a single plane. Each filament is bonded to adjacent filaments under such separating elongation (or bonding power) that the assembly maintains the tape shape (without separation into individual filaments) under normal handling but is easily separated into individual filaments when the filaments are pulled from each other for feeding to a knitting of weaving machine. It has been found that, in view of actual operation in knitting or weaving, the separating elongation (as determined in the manner to be explained later) is preferably less than 150%, more preferably less than 50%.

The finesness (denier) of each filament and the number of filaments to be bonded or adhered together into a tape shape may vary over a wide range depending upon the particular knitting or weaving machine to which the filaments separated from the tape are to be fed and also upon the particular product to be produced from the elastic filaments. Generally, ten or more (particularly 50 or more) filaments are bonded together to form the tape-shaped assembly, each filament generally being 20-2000 deniers (particularly 50-1000 deniers).

The filaments may be made from any synthetic elastic polymer which can be melt spun into elastic filaments. Examples of melt-spinnable polymers are various elastic block copolymers such as polyurethanes, polyester-polyethers, polyamide-polyethers, polyester (aliphatic)-polyesters (aromatic), etc. Since these elastic polymers and their melt-spinning are well known in he art, and since the essence of this invention is not in the use of particular or special elastic polymer, no further explanation thereabout will be required.

As mentioned above it is preferable that the separating elongation (bonding power) between the adjacent filaments in the tape-shaped assembly is less than 150%. The separation elongation referred to throughout the specification and claims is determined at 20 C. in the following manner. Thus, referring to FIG. 2, a sample A (filament assembly in the form of tape) to be measured is fitted to a proper tensile strength testing machine, for example, Tensilon UTM manufactured by Toyo Measuring Instrument Co., Ltd. as shown. One filament 2 separated off in advance by a proper length is clamped by a pulling chuck 3 and the remaining filaments 4 are held at one edge with a fixed chuck 5 connected to a load cell 6. The portion 7 of the sample where the filament 2 is not separated is not fixed but is left extended in a horizontal direction on a proper plate 8. There is applied a pulling force at a pulling velocity of mm./min. and the elongation of the filament 2 at which separation occurs is measured. The ratio of the elongation to the original length, expressed in percentage, is the separating elongation. Fve filaments selected at substantially equal intervals except at both edges are subjected to measurements at 5 points at intervals of 10 cm. in the lengthwise direction. The mean value of a total of 25 measurements is taking as separating elongation of the sample.

The tape-shaped filament assembly may be produced byarranging a desired number of melt-spun filaments while they are still sticky or adhesive on a plane in such a manner that they are in side by side, i.e. parallel, contact and are self-bonded'together in the form a longitudinal tape.

Alternatively, a plurality of filaments (monofilaments or fuse-bonded multi-filaments) prepared in a conventional manner and which are not sticky or adhesive are arranged in side by side contact in parallel relation on a plane and are applied with heat or a solvent to render the filaments sticky or adhesive so that they are selfbonded together in the form of a longitudinal tape.

When the elastic polymers are melt-spun in a usual manner, the filaments show a very low rate of crystallization so that the filaments have a considerable tackiness even after they have been cooled. Therefore, it is possible to melt-spin and cool the filaments in air or aqueous cooling medium in a conventional manner and then to arrange them in parallel so that they are bonded together in the form of a tape. However, in this case it is not easy to control the bonding power between the adjacent filaments. In fact, it has been found that, in the tapeshaped filament assembly prepared in the above manner, the bond of the adjacent filaments is, in many cases, too strong to satisfy the before mentioned preferable separation elongation, i.e. less than 150%. If the bonding power is unduly high, the tape would not be separated into individual filaments unless each filament is strongly pulled or considerably elongated. This would cause difiiculty in the knitting or weaving operation. This drawback may be overcome if the spun-filaments are sufiiciently crystallized before they are bundled in a plane for mutual bonding. However, this is time-consuming.

We have found that the tackiness of such filaments may be effectively controlled within a very short time if a tackiness controlling agent such as an oiling agent, surface active agent and the like having an action of reducing the tackiness of the filaments is deposited on or applied to the spun filaments before they are bonded together. The kind of the tackiness controlling agent, the time of the application and amount of the tackiness controlling agent may be properly selected so that the separating elongation of each filament of the product is less than 150%, more preferably less than 50%.

The tackiness controlling agent may be any which is capable of reducing the tackiness of the spun filaments but does not damage or deteriorate the elastic filaments. As particularly preferable examples, there can be enumerated oiling agents such as silicone oils, low molecular weight polyethylenes, saturated fatty acids and liquid paraffins which are capable of forming aqueous emulsions. But the tackiness controlling agent is not limited to them. The tackiness controlling agent is applied to the filaments before they are arranged in parallel and side by side contact for bonding. The application of the tackiness controlling agent to the spun-filaments may be conducted in any method. However, it is preferable to add the tackiness controlling agent to the aqueous cooling bath and to pass the melt-spun filaments through so that both cooling of the filaments and the application of the tackiness controlling agent thereto are conducted simultaneously. It is also possible that a roller coated with the tackiness controlling agent is contacted with the surfaces of the already cooled and solidified filaments. The filaments on which the tackiness controlling agent has been deposited are arranged in parallel and side by side contact in a plane on a roller or pin and taken-up. In this bundling step, there is no particular difliculty and, even if no special guide is used, when the filaments are takenup in side by side contact they will approach and contact each other to become self-bonded.

Another method for controlling the bonding power (separating elongation) between adjacent filaments in the tape-shaped filament assembly is to stretch or draw the tape-shaped filament assembly already prepared in the above mentioned manner with or without using the tackiness controlling agent. It has been found that even if the bonding power in a filament tape assembly is unduly strong, it can be reduced to a desired extent (less than 150%, preferably less than 50%) when the tape-shaped assembly is properly stretched or drawn. The higher the draw ratio, the lower the separating elongation. When the tackiness controlling agent has not been applied, it is preferable to draw the tape-shaped assembly at least 2 times the length. Generally, by drawing the tape-shaped assembly 3 times or more the length, the separating elongation is reduced to less than 100%. Thus, by simply adjusting the draw ratio, the separating elongation can be controlled as desired. The drawing may be conducted at a temperature less than C. Most conveniently, the drawing is effected at room or normal temperature.

If a tackiness controlling agent has already been applied to the filaments before being formed into a tapeshaped assembly, the separating elongation has already been decreased to a certain extent. Therefore, in such case, the drawing operation may not always be necessary, although it is preferable also to conduct the drawing. When drawing is conducted in such case, the draw ratio may be lower as compared with those cases where the tackiness controlling agent has not been applied.

When drawing has been conducted, it is preferable that the resulting tape-shaped filament is subjected to a heat relax treatment under no tension at a temperature from 80 C. to 170 C. but below the melting point of the polymer forming the filaments. This heat treatment has no noticeable influence on the separability of the filaments but is desirable to improve the elastic filament properties.

As already described, from the viewpoint of the easiness in filament separating, knitting or weaving, it is preferable that the separating elongation of the filaments in the assembly is less than 150%, more preferably less than 50%. The range of the bonding strength allowable to keep the separating elongation in such preferred range is different depending on the particular material of the filament. Thus, the larger the Youngs modulus of the filament, the larger the allowable bonding strength. It is desirable to the production and use of such elastic filament assembly that the range of the allowable bonding strength is large. In such sense, it is desirable that the elastic property of the filament should be such that the modulus at elongation at 20 C. is more than 0.04 g./ (1., more preferably more than 0.05 g./ d.

The tape-shaped assembly of elastic filaments according to this invention may be used in place of conventional already warped elastic filaments or yarns to be fed to a knitting or weaving machine. Thus, for example, a tape wherein about 50l00 mono-filaments have been bonded together as explained hereinbefore is wound up in a roll or contained in a proper magazine and is fed to a knitting station or weaving station where the tape is separated into individual filaments, which are then fed to the knitting or weaving machine. No special warping operation or machine is required in this case.

FIG. 3 shows a schematic view of an apparatus for producing a tape-shaped filament assembly according to this invention. Thus, an elastic polymer is melted and extruded through an extruder 9 through a spinnerette 10 having a desired number of orifices to form filaments 11. The formed filaments 11 are continuously passed through a cooling bath 12 which contains an aqueous cooling medium (usually Water) and which may also contain a tackiness controlling agent as explained before. The filaments 11 are guided around a roller 13 and up to a fixed pin 14. During the upward movement from the cooling bath the filaments 11 are collected together in a plane and are brought to side-by-side parallel contact on the pin 14 and self-bonded together to form a tape-shaped unitary assambly A. Then the tape A is drawn between multi-stage rollers 15 and 16. As explained before, this drawing step is not always necessary, although it is preferable to be provided. Then the tape A is subjected to a heat relax treatment in a heating zone 17 arranged between multistage rollers 16 and 18. Indicated with 19 are conventional oiling rollers. The tape A subjected to the oiling at 19 is discharged into a container 20 through a pair of nip rollers 21.

The invention will be illustrated in the following examples wherein all parts are by weight.

EXAMPLE 1 An elastic filament assembly in a tape shape was produced by using an apparatus such as schematically shown in FIG. 3 except that the members 16, 17 and 18 are omitted. Thus, pellets of a polyester-polyether block copolymer obtained by polycondensing 2800 parts of dimethyl terephthalate, 2200 parts of ethylene glycol and 7500 parts of polytetramethylene glycol having an average molecular weight of 2.000 in the presence of 5 parts of zinc acetate, 5 parts of germanium dioxide and 150 parts of titanium oxide and 150 parts of titanium oxide, were melted at 220 C. in the extruder 9. Filaments 11 extruded through the spinnerette of 60 orifices were first introduced into cooling water bath 12 at 25 C. containing a tackiness controlling agent and then collected on the pin 14 in side-by-side contact in a plane to self-bond together forming a tape-shaped filament assembly. The filament assembly was oiled at the oiling rollers 19, 19 and was then discharged in the containing can 20. The monofilament in the product was 420 deniers. Various tapeshaped assemblies were prepared in the above manner with or without using various tackiness controlling agents. In respect of each product, the separating elongation was measured. The results are as shown in Table 1.

TABLE 1 Tackiness controlling agent Concentration percent in water Separating elongation,

Kind percent Saitekkusu Silicone 50 Do PPPPPP memos-Ma 0 Soluol 8134 Note.-Saitekkusu Silicone 50 is produced by Goo Ohemicl Industries,

Ltd.,;of Japan and has the following composition: Percent Silicone oil (350 c.s., dimethyl type) 0 Sorbltan monostearate Liquid paratfin (R.W. 32 sec. at 50 C. Nonionic phosphate Nonionic surface active agent (lauryl ether type) 8. The rest being water.

Polyethylene wax consists of 60% low molecular weight polyethylene, MC Polywax 22 (product of Mobil 011 Company, Ltd.) and 40% nonylphenol-ethylene oxide reaction product.

Soloul 3134 is the product of Kao Soap Company, Ltd., Japan and consists mainly of a saturated fatty acid ester and contains about 20% of an ether type nonionic surface active agent as an assistant.

EXAMPLE 2 An elastic filament tape-shaped assembly was prepared in the same manner as in Example 1 by using Paraprene 228 (product of Hodogaya Chemical Company, Ltd.) which is a polyester-polyurethane block copolymer as an elastic polymer material. However, in this example, no fixed pin 14 was used and the filaments were bundled on the multistage rollers 15. The melting temperature in the extruder was 190 C. The cooling water temperature was 20 C. The monofilament fineness for 500 deniers. The results of measurement of separating elongations of the filaments in the resulting tape products are as shown in Table 2.

TABLE 2 Tackiness controlling agent Concentration percent in water Separating elongation, percent Kind Saitekkusu Silicone 50 OONQQQ o Soluol 3134 EMMPLE 3 (average molecular weight of 2000) were subjected to esterexchanging reaction and polycondensed in the presence of 5 parts of zinc formate, 5 parts of germanium dioxide and 1500 parts of titanium dioxide to obtain a polyester-polyether block copolymer having a desirable elasticity. An elastic tape assembly of filaments was produced by using an apparatus as shown schematically in FIG. 3. The polymer pellets were melted at 230 C. in the extruder 9 and the melt was extruded through the spinnerette 10 of orifices. The formed filaments 11 were cooled in the bath 12 consists only of water at 25 C. so as to be cooled but not to be bonded with each other. The filaments were then bonded in the form of a tape on the fixed pin 14 in the course from the roller 13 to the multistage rollers 15. Then the tape-shaped assembly A was drawn at the normal temperature between the multistage rollers 15 and 16 and was relaxed to shrink in the heating zone 17 at C. between the multistage rollers 16 and 18. The final monofilament fineness was about 420 deniers. Various tape-shaped assemblies were prepared by varying the draw ratio and the separating elongation was measured in respect of each product. The results are as shown in Table 3.

TABLE 3 Separating elongation (percent) 98 30 18 Draw ratio:

EXAMPLE 4 Various tape shaped filament assemblies were prepared in the same manner as in Example 3 except that various tackiness controlling agents were added to the cooling Water bath 12. The separating elongation was measured in respect of each of the products. The results are as shown in Table 4.

Paraprene 228 was melted at C. in the extruder 9 and the melt was extruded through the spinnerette 10 of 80 orifices to obtain elastic filaments. A tape shaped assembly of the elastic filaments was prepared by using the apparatus schematically shown in FIG. 3 in the same manner as in Example 1. However, in this case, the heat relaxing zone 17 was at 80 C. and the final monofilament fineness was 4.20 deniers.

'Ihe separating elongations of the products obtained by varying the draw ratio are shown in Table 5.

TABLE 5 Separating elonga- Draw ratio: tion (percent) 7 EXAMPLE 6 The separating elongations were measured in respect of the products obtained in the same manner as in Example except that the same tackiness controlling agents as used in Example 4 were added to the cooling bath 12. The results are shown in Table 6.

TABLE 6 Taekiness controlling agent EXAMPLE 7 A power net was knitted of each of the products obtained in Example 3. In case the separating elongation was 170%, the elongation and its fluctuation at the time of separating the tape into the individual filaments were large so that the obtained power net had many pleats and was improper for practical use. Further, even in the preparatory operation of manually separating the filaments and setting the monofilaments on the knitting machine at the time of starting the knitting, then was such difiiculty in the workability as difiiculty in the separation into individual filaments. Even with the product the separating elongation of which was 98%, there was encountered with some difficulty in the above mentioned preparatory operation, but it was not such as adversely alfecting the knitting operation and product quality. With the products the separating elongation of which was 30% and 18%, both workability and product quality were satisfactory. Further, even with such low separating elongation (hence, low in the bonding strength), the filaments did not naturally separate while the tape was being handled for storing, conveying and preparatory operation.

What we claim is:

1. A method of producing a tape-shaped assembly of at least 10 elastic filaments parallelly arranged and selfbonded together under a bonding force such that the separating elongation between adjacent filaments is less than comprising melt-spinning an elastic polymer into filaments, cooling the spun filaments, arranging the cooled filaments in a parallel plane to effect side-by-side contact of adjacent filaments While the filaments are still tacky or adhesive, thereby forming a unitary tape-shaped assembly, and drawing the assembly at a draw ratio of at least 2 to adjust the separating elongation between filaments to less than 150% without separating the assembly into individual filaments.

2. The method according to claim 1, wherein the drawn assembly is subjected to a heat relax treatment.

3. A method of producing a tape-shaped assembly of at least 10 elastic filaments parallelly arranged and selfbonded together under a bonding force such that the separating elongation between adjacent filaments is less than 150%, comprising melt-spinning an elastic polymer into filaments, cooling the spun filaments, applying a tackiness controlling agent to the filaments, arranging the resultant filaments in a parallel plane to effect sideby-side contact of adjacent filaments while the filaments are still tacky or adhesive, thereby forming a unitary tapeshaped assembly, and drawing the assembly at a draw ratio of at least 2 to adjust the separating elongation between adjacent filaments to less than 150% without separating the assembly into individual filaments.

4. The method according to claim 3, wherein the drawn assembly is subjected to a heat relax treatment.

References Cited UNITED STATES PATENTS 3,154,611 10/1964 Dinsbergs 264DIG. 77 3,464,197 9/1969 Martin 1'61143 3,536,803 10/1970 Epstein et a1. 264-342 RE 3,258,378 6/1966 Kelsey 156-167 OTHER REFERENCES Cook, 1. Gordon: Handbook of Textile Fibres, Merrow Publishing Co., Ltd., England, 1968, p. 672.

ROBERT F. BURNETT, Primary Examiner R. O. LINKER, JR., Assistant Examiner US. Cl. X.R. 

